| From 0afefd3e3efc93b51886838b055f91d8f2c5428b Mon Sep 17 00:00:00 2001 |
| From: Dominik Behr <dbehr@chromium.org> |
| Date: Tue, 1 Apr 2014 18:31:12 -0700 |
| Subject: [PATCH] xrandr: fix setting of linear gamma table |
| |
| Current linear gamma table generation assues 256 entry, 8-bit precision |
| gamma table. This patch uses floating point arithmetic to create correct, |
| full precision gamma table for any case. Similar patch again master branch |
| has been submitted for consideration upstream to xorg-devel mailing list. |
| This patch allows us to test gamma table functionality on Samsung Exynos |
| based hardware which has 17 entry 8-bit precision gamma table. |
| |
| BUG=chromium:353360 |
| TEST=DISPLAY=:0.0 xrandr --output LVDS-1 --mode 1366x768 -gamma 0:0:0 on\ |
| peach-pit with gamma functions enabled in kernel and xf86-video-armsoc |
| |
| Signed-off-by: Dominik Behr <dbehr@chromium.org> |
| --- |
| xrandr.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/xrandr.c b/xrandr.c |
| index 10d034d..a5c3e14 100644 |
| --- a/xrandr.c |
| +++ b/xrandr.c |
| @@ -1319,21 +1319,21 @@ set_gamma(void) |
| |
| for (i = 0; i < size; i++) { |
| if (output->gamma.red == 1.0 && output->brightness == 1.0) |
| - gamma->red[i] = (i << 8) + i; |
| + gamma->red[i] = (double)i / (double)(size - 1) * 65535.0; |
| else |
| gamma->red[i] = dmin(pow((double)i/(double)(size - 1), |
| output->gamma.red) * output->brightness, |
| 1.0) * 65535.0; |
| |
| if (output->gamma.green == 1.0 && output->brightness == 1.0) |
| - gamma->green[i] = (i << 8) + i; |
| + gamma->green[i] = (double)i / (double)(size - 1) * 65535.0; |
| else |
| gamma->green[i] = dmin(pow((double)i/(double)(size - 1), |
| output->gamma.green) * output->brightness, |
| 1.0) * 65535.0; |
| |
| if (output->gamma.blue == 1.0 && output->brightness == 1.0) |
| - gamma->blue[i] = (i << 8) + i; |
| + gamma->blue[i] = (double)i / (double)(size - 1) * 65535.0; |
| else |
| gamma->blue[i] = dmin(pow((double)i/(double)(size - 1), |
| output->gamma.blue) * output->brightness, |
| -- |
| 1.9.1.423.g4596e3a |
| |
